Power operated rotary knives have been used in commercial meat processing operations to trim fat and connective tissue from meat, trim pieces of meat from bones, and to produce meat slices. Such knives usually comprise a handle, blade housing and a rotary knife blade. The knife operator wields the knife relatively freely at a meat cutting work station that is remote from a driving motor.
In many countries of the world, for example, China, chicken feet and paws are a staple food item. As generally used, a chicken paw is a portion of the lower leg (metatarsus) of a chicken, while chicken foot or chicken feet typically includes the chicken paw plus a portion of the shank of the leg of the chicken. In FIG. 1, a chicken is shown generally at 10, a chicken paw is shown generally at 12, while a chicken foot is shown generally at 14. As can be seen, the chicken foot 14 includes a portion of a shank 16 of a chicken leg 18. For purposes of this application, both chicken paws 12 and chicken feet 14 will be referred to generally as chicken paws 12.
According to the USDA, China imports approximately 300,000 to 350,000 metric tons of chicken feet and chicken paws per year and the U.S. is the single largest chicken paw supplier to China. USDA Foreign Agriculture Service GAIN Report (Global Agriculture Information Network), GAIN Report Number CH7006, Date: Feb. 7, 2007, Peoples Republic of China—Poultry and Products—Chicken Paw, Wing and Wing Tip Exports to China 2007, by Casey Bean, Joseph Jacobson and Suzanne Ryan. The price paid for chicken paws depends, among other things, on the quality of the paws. The quality of a chicken paw 12 is dependent on a number of factors, one of which is the presence or absence of damaged or discolored regions of the paw.
The metatarsal pad, shown generally at 20 in FIGS. 1-3, is a large, central fleshy pad located at on a bottom of the paw 12 at the end of the tarsometatarsal bone (not shown). A generally planar, lower surface 22 of the metatarsal pad 20 contacts a ground or surface 24 when the chicken 10 walks or stands. The metatarsal pad 20 contacts the ground when the chicken walks and extends between the metatarsal fold 26 and the bases of the three toes 28, 30, 32. The metatarsal pad 20 is highly desired because of its food value. However, the ground or surface 24 that chickens walk or stand on is often covered in highly acidic chicken manure. Therefore, a portion 34 of the metatarsal pad 20, generally corresponding to the planar, ground contacting portion 22 of the pad 20, will often be damaged and/or discolored due to the acidic action of chicken manure on the pad 20 during the life of the chicken 10. A damaged and/or discolored portion (shown in dashed line as 34 in FIG. 3) of a metatarsal pad 20 will be generally referred to herein as the undesirable portion 34 of the metatarsal pad 20. If a lot of chicken paws 12 is being processed, failure to completely remove the undesirable portion 34 of each metatarsal pad 20 may result in: a) a reduction in the quality grade that the lot of chicken paws would otherwise receive; and/or b) a rejection of the entire lot of chicken paws.
Accordingly, it is desired to remove the undesirable portion 34 of the metatarsal pad 20 during processing of the chicken paw 12. At the same time, since the metatarsal pad 20 is highly desired for its food value and contributes to the weight of the chicken paw 12, it is desired that trimming of the metatarsal pad 20 be kept to a minimum necessary to remove the undesirable portion 34 of the pad 20 while leaving the remaining undamaged portion 36 of the pad. Typically, the undesirable portion 34 constitutes a relatively thin layer adjacent the ground contacting surface 22 of the metatarsal pad 20, so it desired to remove a thin layer of the pad 20 to remove the undesirable portion 34 completely while still leaving as much of the underlying undamaged portion 36 of the pad 20 intact as possible.
Hand trimming of the metatarsal pad 20 using straight or curved knives or another tool, such as a cheese grater, is both slow and laborious. Additionally, hand trimming is prone to either: 1) trimming substantially more of the undamaged portion 36 of the metatarsal pad 20 than necessary to remove the undesirable portion 34 of the pad; or 2) incomplete removal of the undesirable portion 34 of the pad 20.
What is desired is a method of trimming an undesirable portion of a metatarsal pad of a chicken paw that is faster than hand trimming, suitable for use by operators with minimal training, easier and more ergonomically correct than hand trimming, and that facilitates trimming the undesirable portion of the metatarsal pad without substantial removal of undamaged portions of the metatarsal pad.